一般来说：

 静态常量
 

由于它尊重范围和类型是安全的。

唯一的告诫我可以看到：如果你想在命令行上可能定义的变量。还有一种替代方案：

  #IFDEF VAR //非常不好的名字，不够长，过于笼统，等等。
  静态INT常量VAR = VAR;
＃其他
  静态INT常量VAR = 5; // 默认值
＃万一
 

只要有可能，而不是宏/省略号，使用类型安全的替代品。

如果你真的需要去一个宏（例如，你希望 __ FILE __ 或 __ LINE __ ），然后你***命名您的宏非常小心：在其命名约定的升压建议全部大写，由项目（这里BOOST_）的名称开始，在应聘一个库，你会发现这是（一般）的特定区域（库），然后用一个有意义的名称的名称

这通常使得冗长的名字：）

Which one is better to use among the below statements in C?

static const int var = 5;

or

#define var 5

or

enum { var = 5 };

Generally speaking:

static const

Because it respects scope and is type-safe.

The only caveat I could see: if you want the variable to be possibly defined on the command line. There is still an alternative:

#ifdef VAR // Very bad name, not long enough, too general, etc..
  static int const var = VAR;
#else
  static int const var = 5; // default value
#endif

Whenever possible, instead of macros / ellipsis, use a type-safe alternative.

If you really NEED to go with a macro (for example, you want __FILE__ or __LINE__), then you'd better name your macro VERY carefully: in its naming convention Boost recommends all upper-case, beginning by the name of the project (here BOOST_), while perusing the library you will notice this is (generally) followed by the name of the particular area (library) then with a meaningful name.

It generally makes for lengthy names :)